Responsive Self-Assembled Nanotransporters as Multi Faceted Controlled Release Systems

A series of modified biopolymers was designed to self-assemble into nanotransporter aggregates, which may be implemented as responsive multi faceted controlled release systems. For this end, antimicrobial aliphatic aldehydes were coupled to the antimicrobial biopolymer chitosan via a reversible dynamic covalent N-imine Schiff base linkage. The conjugated aldehydes’ introduced hydrophobicity, along with chitosan’s hydrophilic nature, yielded amphiphilic block copolymers. These modified biopolymers undergo self-assembly into nano sized aggregates that successfully envelope both hydrophobic and hydrophilic active payloads as either micelles or vesicles, respectively. Active payloads can then be released in a measured and controlled fashion as a response to an external pH stimulus. Upon acidic hydrolysis, the systems’ aggregate structure immediately breaks down to their original constituents, which until then have been dormant in terms of bioactivity. This novel approach allows for a controlled multi facet attack not only by the active payload, but also by all of the system’s other components individually.